Slovakia’s defense ministry said on Friday it was in talks to buy either American F-16s or Swedish Gripen fighter jets to replace its aging Russian-made MiG-29s, according to Reuters.

The ministry said it would submit an analysis of the two options by June 29 for government approval.

Slovakia, a member of NATO, has a maintenance contract with Russia for its 12 MiG-29s until autumn 2019. That contract may need to be extended even if the government agrees to buy new jets by the end of this year, since the new jets typically take 18 to 24 months to deliver.

“Both options are good. F-16s are more expensive and they may take until around 2023 to be delivered,” Jaroslav Nad from the Slovak Security Police Institute said.

Neighboring Hungary and the Czech Republic already operate Gripens, built by Saab. Poland flies F-16s, built by Lockheed Martin Corp, and may buy more.

Slovakia has a “joint sky” agreement with the Czech Republic, which leases 14 Gripens. The agreement means the two would help protect each other’s air space beyond the standard air defense cooperation within NATO. If Slovakia buys Gripens, they could also share maintenance and pilot training.

Slovakia is due to spend about 6.5 billion euros ($8.11 billion) by 2030 to modernize its military. Defense spending is due to rise from 1.1 percent of gross domestic product last year to 1.6 percent in 2020 and 2.0 percent by 2024.

In November 2017, the government approved plans to build 81 eight-wheeled armored personal carriers with the Finnish defense company Patria, to replace outdated personnel carriers.

The ministry is set to pick a partner to build 404 four-wheeled armored vehicles this year.